Anticholinergic Toxicity in the Emergency Department

Audience Emergency medicine residents, internal medicine residents, family medicine residents, community physicians, pediatricians, toxicology fellows Introduction There are over 600 compounds which contain anticholinergic properties.1 Medications with anticholinergic properties include antihistamines, atropine, tricyclic antidepressants, antipsychotics, topical mydriatics, antispasmodics, sleep aids, and cold preparations. 1–4 Plants that possess anticholinergic properties such as jimson weed, and street drugs cut with anticholinergics such as scopolamine are sources of accidental or intentional ingestion.1,2,4 Anticholinergic toxicity can cause a myriad of signs and symptoms, including agitation, seizures, hyperthermia, cardiac dysrhythmias, and death. Since poisoning from anticholinergic medications is frequently encountered in the emergency department, is it essential that emergency physicians be familiar with how to manage this toxidrome. This simulation case will allow the learner to evaluate and manage a patient presenting with anticholinergic toxicity. Educational Objectives By the end of this simulation case, learners will be able to: 1) describe the classic clinical presentation of anticholinergic toxicity, 2) discuss common medications and substances that may lead to anticholinergic toxicity, 3) recognize the electrocardiogram (ECG) findings in anticholinergic toxicity that require specific therapy, and 4) review the management of anticholinergic toxicity. Educational Methods This simulation is taught using a high- or moderate-fidelity manikin. Research Methods The educational content was evaluated by the learners immediately after completion and debriefing of the scenario. This case was initially piloted with approximately twenty emergency medicine residents. The group was comprised of first, second-, and third-year residents from a three-year emergency medicine residency. The efficacy of the content was assessed by oral feedback. Results Overall, the case was well received by learners, who felt it was useful and were engaged throughout the session. The overall feedback was positive and the case was well-received by learners. Discussion This scenario was eventually tested on over 100 learners over the course of several years, and the overall feedback was positive. It was found to be effective when debriefing sessions using various debriefing techniques (such as advocacy/inquiry) were utilized to discuss both the learners’ performance in the case, as well as the debriefing pearls (located at the end of this manuscript). Topics Anticholinergic toxicity, altered mental status, toxicology.


Case Description & Diagnosis (short synopsis):
An 18-year-old male is brought in by ambulance after being found altered and wandering around a mobile home park. Upon arrival to the emergency department, he is confused, combative, febrile, and tachycardic. Upon further questioning of his friend at bedside, it is discovered that the patient and his friends were drinking tea made out of jimson weed and liquid diphenhydramine, as part of a viral online social media challenge, prior to his altered level of consciousness. The patient is ultimately found to be presenting with an anticholinergic toxidrome secondary to consumption of jimson weed and diphenhydramine. Background and brief information: The scenario takes place in an emergency department at a community hospital. The patient is an 18-year-old male brought in by paramedics with a chief complaint of altered mental status.

Initial presentation:
The patient is confused and intermittently agitated upon arrival. His vital signs are significant for a fever and tachycardia. His physical exam is significant for dry and flushed skin, dilated pupils, and altered mental status. He is unable to provide further history.
How the scene unfolds: The patient arrives to the emergency department confused and unable to provide further history. If asked, the paramedics will report that the patient was found wandering about his mobile home park confused. They will report that the patient was tachycardic on scene, and that his finger-stick blood glucose was normal. They will state that the patient was intermittently combative en route, and would not cooperate with the nonrebreather face mask that they attempted to place on him. If the participants ask the patient's friend at bedside for more information, he will state that the patient and some friends were taking part in a viral online social media challenge, and were drinking a tea made out of jimson weed and liquid diphenhydramine, which the patient consumed shortly before becoming altered.
On arrival, the patient is tachycardic and hyperthermic. His physical exam is significant for dry, flushed skin, dilated pupils, and altered mental status. The patient's ECG will be significant for tachycardia with a QRS >100ms. The participants should make the diagnosis of anticholinergic toxicity. The participants may initiate treatment with activated charcoal. The participants should also contact the poison control center. They may control the patient's agitation using benzodiazepines. If the diagnosis of anticholinergic toxidrome is delayed and benzodiazepines are not administered, the patient will become increasingly agitated and will have a seizure.
The participants should recognize the concerning finding of the QRS >100msec on ECG, and should administer sodium bicarbonate. If the participants do not recognize this, but consult the poison control center, the toxicologist will prompt them to review the ECG and initiate sodium bicarbonate. If sodium bicarbonate is not given, the patient will go into ventricular fibrillation. If the participants administer physostigmine, the patient will go into cardiac arrest. The patient should ultimately be admitted to the intensive care unit for further observation and management. • History of present illness: The patient is an 18-year-old male who presents brought in by paramedics with altered mental status. The patient will be too altered to provide any history. If asked, the paramedics will report that the patient was found wandering about a mobile home park altered. They will report that he was tachycardic in the field, and that his finger-stick blood glucose was normal. They will state that he was intermittently agitated en route. If the friend at bedside is questioned, he will state that the patient and his friends were drinking tea made out of jimson weed and liquid diphenhydramine earlier in the day. • Past medical history: Unable to obtain from patient due to altered mental status • Past surgical history: Unable to obtain from patient due to altered mental status • Patient's medications: Unable to obtain from patient due to altered mental status • Allergies: Unable to obtain from patient due to altered mental status • Social history: Unable to obtain from patient due to altered mental status • Family history: Unable to obtain from patient due to altered mental status Secondary Survey/Physical Examination:

INSTRUCTOR MATERIALS
• General appearance: Awake, confused, dazed look on face, appears to be responding to internal stimuli If asked, patient's friend will state that patient was making tea with jimson weed and liquid diphenhydramine, which he consumed prior to becoming altered.
Physical exam will be significant for dry, warm, flushed skin, mydriasis, tachycardia, and confusion.
Finger-stick glucose will be normal. If diagnosis of anticholinergic toxicity not made by this time and patient not given benzodiazepine, patient will become increasingly agitated and have a seizure.
If patient has seizure, it will resolve with benzodiazepine administration. If benzodiazepine is given, vitals will stabilize, and move on to time 6:00. If benzodiazepine is not given, patient will go into cardiac arrest and expire. If poison control/toxicology consult obtained, they will prompt participants to review ECG and give sodium bicarbonate. They will also recommend that activated charcoal be given. They will recommend against physostigmine, because patient's QRS is >100ms.

If sodium bicarb is given:
Patient's vital signs will remain stable, proceed to time 10:00 If sodium bicarb not given: Patient will go into Ventricular fibrillation. If ACLS started, patient will not obtain return of spontaneous circulation (ROSC) until sodium bicarb is given. If sodium bicarb given, patient will obtain ROSC, proceed to time 10:00. If sodium bicarb still not administered, patient will expire and case will end.
If physostigmine is given, patient will decompensate into cardiac arrest and case will end. intubation, and will ultimately go into cardiac arrest and expire.

Diagnosis:
Anticholinergic toxicity secondary to jimson weed ingestion

Anticholinergic Toxicity
• Introduction: o There are over 600 compounds which contain anticholinergic properties. 1 Medications with anticholinergic properties include antihistamines, atropine, tricyclic antidepressants, antipsychotics, topical mydriatics, antispasmodics, sleep aids, and cold preparations. 1,2,3,4 Plants such as jimson weed (datura stramonium) and deadly nightshade (atropa belladonna) also have anticholinergic properties and are a common source of accidental or intentional ingestion. 1,2,4 Street drugs such as heroin and cocaine have been known to be cut with anticholinergics such as scopolamine. 1,2 Thus, it is not surprising that anticholinergic poisonings are frequently seen in the emergency department, and recognition of the anticholinergic toxidrome is a necessary clinical skill. 1,4 • Pathophysiology and Clinical Manifestation: o Muscarinic acetylcholine receptors are located in the central nervous system, heart, smooth muscle, secretory glands, and ciliary body of the eye. 1 o Normally, the neurotransmitter acetylcholine binds to these muscarinic receptors 1 o Anticholinergic drugs competitively inhibit this binding, producing the following clinical effects: "Mad as a hatter" Blockage of CNS muscarinic receptors • Delirium, hallucinations, anxiety, agitation, seizure • CNS symptoms most worrisome, considered "severe" toxicity "Blind as a bat" Pupillary dilation and ineffective accommodation • Blurry vision "Dry as a bone" Blockage of sweat gland muscarinic receptors àlack of sweating • Tachycardia • Dysrhythmias (widened QRS, prolonged QT) • Management: o Stabilization of airway, breathing, and circulation is paramount, as well as initiating IV access and placing patient on cardiac monitoring and pulse oximetry. 1 o Decontamination: § Activated charcoal may be considered as long as patient is able to protect their airway or if they are intubated, though patients shouldn't be intubated solely for the purpose of administering activated charcoal. 1,2,4 § May be considered even if ingestion occurred more than one hour prior, because anticholinergics decrease gastrointestinal motility.